Plant effluent was pumped from a manhole to a 300 gallon coagulation / pH buffer tank with a flash-mix agitator. The coagulated / pH adjusted water then gravity-flowed to a 300 gallon flocculation tank with a slow-mix agitator where a flocculant was dosed. The flocculated water then gravity-flowed to a P-TEC Model MD-2442 20 GPM Dissolved Air Flotation (DAF) System. Additional ancillary equipment was also provided; (feed pumps, chemical pumps, tanks, etc.).

TESTING PROCEDURES:

Prior to each test run, the water was jar-tested to determine optimal chemical dosing rates, then the system was started-up and stabilized before sampling took place. Flow rate, chemical dosing, aeration system, etc. were monitored to insure consistent operation.

500-ml samples of the raw wastewater influent and treated effluent were taken every hour to produce daily composite samples. A sludge sample was collected for moisture analysis in order to estimate volume produced.

Note for ALL tests: The pH was maintained at between 6.0 and 7.0 using 150 PPM (by volume) of 66o Be sulfuric acid (H2SO4) during the “3P” and DAF only trials. Little or no acid was required for the aluminum chloride and polymer trial because the 600 PPM dose of aluminum chloride itself lowers the pH to ~6.5. Average influent pH was approximately 9.0, but was observed as low as 4.5 and as high as 11.5.